[WIP] Add a custom bootloader

bootloader/boot.asm

@@ -26,6 +26,43 @@ boot:
  or eax, 0x1 ; on special
  mov cr0, eax ; CPU reg cr0
 
+
+; ---------------------------------------------------------------------
+; now we will read the disk for our kernel code
+; it is recommended that the disk read must be tried atleast thrice
+
+load_disk:
+
+ mov ah, 0x02 ; the BIOS routine for reading disk sectors
+ mov al, 0x01 ; the number of sectors to read
+ mov ch, 0x0 ; track/cylinder number
+ mov cl, 0x3 ; sector number
+ mov dh, 0x0 ; head number
+ mov dl, 0x1 ; drive number
+
+ int 13h ; on return, ah = status, al = number of sectors read,
+ jc load_disk_error ; carry = 0 if success, 1 if fail
+ jmp load_disk_done
+
+ ;cmp al, 0x01
+ ;jne load_disk_error
+
+load_disk_error:
+ jmp load_disk
+
+load_disk_done:
+ cli
+ hlt
+
+
+
+ mov ax, 0x1000
+ mov es, ax
+ mov bx, 0x0
+
+ jmp 0x1000:0x0
+ hlt
+
  jmp CODE_SEG:boot2 ; long jump to the code segment
 
 
@@ -79,32 +116,6 @@ boot2:
  mov gs, ax
  mov ss, ax
 
-
-; ---------------------------------------------------------------------
-; let's print something using VGA text
-
- mov ebx, 0xb8000 ; the VGA buffer is located at 0xb8000
- ; we will be sending all text to this
-
- mov esi, hello ; load the string to be printed
-
-.loop:
- lodsb ; load a byte
- add al, 0x0 ; check if it is zero
- jz halt ; halt if it is
- or eax, 0x0200 ; add formatting info
- mov word [ebx], ax ; send to VGA
- add ebx, 2 ; increment address
- jmp .loop
-
-halt:
- cli ; clear interrupts flag (block interrupts)
- hlt ; hlt
-
-hello:
- db "I love OSDev. My bootloader is awesome!", 0
-
-
 ; ---------------------------------------------------------------------
 ; mark this as bootable
 

shit.asm

@@ -0,0 +1,25 @@
+; ---------------------------------------------------------------------
+; let's print something using VGA text
+
+ mov ebx, 0xb8000 ; the VGA buffer is located at 0xb8000
+ ; we will be sending all text to this
+
+ mov esi, hello ; load the string to be printed
+
+.loop:
+ lodsb ; load a byte
+ add al, 0x0 ; check if it is zero
+ jz halt ; halt if it is
+ or eax, 0x0200 ; add formatting info
+ mov word [ebx], ax ; send to VGA
+ add ebx, 2 ; increment address
+ jmp .loop
+
+halt:
+ cli ; clear interrupts flag (block interrupts)
+ hlt ; hlt
+
+hello:
+ db "I love OSDev. My bootloader is awesome!", 0
+
+